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The Study for Heavy Fermion State in f- electron pnictides

f电子磷族元素中重费米子态的研究

基本信息

批准号：
03452027
负责人：
SUZUKI Takashi
金额：
$ 4.1万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

We could make remarkable development for the extensive fundarmental properties of Ce monopnictides under ultra high pressure; The transport properties and the change of the Fermi surfaces area under high pressure have been measured. The Fermi surfaces area of the reference system of LaSb increased with increasing pressure as in the usual case. However that of CeAs decreased with increasing pressure. The latter case is clearly due to f electron effect and bring the interesting problem to be solve The neutron diffraction and scattering revealed the variation of complicated magnetic structure and crystalline field splitting with increasing pressure. The magnetization for CeP single crystal have been measured up to 60T and showed nearly 10 step magnetization at the magnetic field just same time for Landau level crossing of the hole Fermi sphere and attracted many interest for this new phenomena. The discovering of largest fermi surface in CeSb by accoustic dHvA effect proved the rightness of the p-f mixing theory. The success of very pured single crystal of LaAs can bring us to new stage ofd extremly low carrier system of 10-4 order of carrier number and expect to clearfy the behavior of the quantum limit of Landau motion for avaiable high magnetic field. The dHvA measurement for the most typical heavy Fermion state of low carrier system of YbAs and could detect the electron and one hole Fermi surface with effective mass below 1 and were not consistent with large coefficient of the electronic specific heat capacity. It should be another hole Fermi surface with very large mass up to several thousand. This large massenhancement is particular point of low carrier system and not seen in usual mettallic heavy Fermion systems. The most impressive discovery in this project is the heavy Fermion state of insulating state in Sm3X4 and suggest the fundermental revolution of usual heavy Fermion concept.

在超高压条件下，Ce单羟基化合物具有广泛的基本性质，可以取得显著的发展；测量了高压下的输运性质和费米表面积的变化。在通常情况下，LaSb参考系的费米表面积随压力的增加而增加。而随着压力的增加，CeAs的浓度逐渐降低。中子衍射和散射揭示了复杂的磁性结构和晶体场分裂随压力增加的变化。对CeP单晶在60T下的磁化强度进行了测量，结果表明，在电场作用下，空穴费米球的朗道水平交叉产生了近10阶的磁化，这一新现象引起了人们的关注。利用声学dHvA效应发现了铯原子中最大费米表面，证明了p-f混合理论的正确性。极纯LaAs单晶的成功将使我们进入10-4阶极低载流子体系的新阶段，并有望阐明在可用的高磁场下朗道运动量子极限的行为。低载流子体系中最典型重费米子态的dHvA测量，只能探测到有效质量小于1的电子和单孔费米表面，与电子比热容系数大不一致。它应该是费米表面的另一个洞，质量非常大，高达几千。这种较大的质量增强是低载流子系统所特有的，在通常的重金属费米子系统中是看不到的。该项目最令人印象深刻的发现是Sm3X4中绝缘态的重费米子态，并提出了通常的重费米子概念的根本革命。